/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.search.function;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Searcher;

import java.io.IOException;
import java.util.Map;

/**
 * <code>LinearFloatFunction</code> implements a linear function over another
 * {@link org.apache.solr.search.function.ValueSource}. <br>
 * Normally Used as an argument to a
 * {@link org.apache.solr.search.function.FunctionQuery}
 * 
 * @version $Id: RangeMapFloatFunction.java 1065312 2011-01-30 16:08:25Z rmuir $
 */
public class RangeMapFloatFunction extends ValueSource {
	protected final ValueSource source;
	protected final float min;
	protected final float max;
	protected final float target;
	protected final Float defaultVal;

	public RangeMapFloatFunction(ValueSource source, float min, float max,
			float target, Float def) {
		this.source = source;
		this.min = min;
		this.max = max;
		this.target = target;
		this.defaultVal = def;
	}

	@Override
	public String description() {
		return "map(" + source.description() + "," + min + "," + max + ","
				+ target + ")";
	}

	@Override
	public DocValues getValues(Map context, IndexReader reader)
			throws IOException {
		final DocValues vals = source.getValues(context, reader);
		return new DocValues() {
			@Override
			public float floatVal(int doc) {
				float val = vals.floatVal(doc);
				return (val >= min && val <= max) ? target
						: (defaultVal == null ? val : defaultVal);
			}

			@Override
			public int intVal(int doc) {
				return (int) floatVal(doc);
			}

			@Override
			public long longVal(int doc) {
				return (long) floatVal(doc);
			}

			@Override
			public double doubleVal(int doc) {
				return (double) floatVal(doc);
			}

			@Override
			public String strVal(int doc) {
				return Float.toString(floatVal(doc));
			}

			@Override
			public String toString(int doc) {
				return "map(" + vals.toString(doc) + ",min=" + min + ",max="
						+ max + ",target=" + target + ")";
			}
		};
	}

	@Override
	public void createWeight(Map context, Searcher searcher) throws IOException {
		source.createWeight(context, searcher);
	}

	@Override
	public int hashCode() {
		int h = source.hashCode();
		h ^= (h << 10) | (h >>> 23);
		h += Float.floatToIntBits(min);
		h ^= (h << 14) | (h >>> 19);
		h += Float.floatToIntBits(max);
		h ^= (h << 13) | (h >>> 20);
		h += Float.floatToIntBits(target);
		if (defaultVal != null)
			h += defaultVal.hashCode();
		return h;
	}

	@Override
	public boolean equals(Object o) {
		if (RangeMapFloatFunction.class != o.getClass())
			return false;
		RangeMapFloatFunction other = (RangeMapFloatFunction) o;
		return this.min == other.min
				&& this.max == other.max
				&& this.target == other.target
				&& this.source.equals(other.source)
				&& (this.defaultVal == other.defaultVal || (this.defaultVal != null && this.defaultVal
						.equals(other.defaultVal)));
	}
}
